Abstract The dramatic increase in utilization of total joint arthroplasty (TJA) (doubled between 1998-2005) has been accompanied by a change in patient's demographic profile. TJA is increasingly being utilized by younger and less functionally debilitated individuals who expect more from the surgery. Knowing that unmet expectations are associated with dissatisfaction and potentially inferior function, addressing these increasing expectations and setting realistically achievable goals for the surgery becomes a real challenge. While surgeons aim to guide expectations through discussions with their patients so surgeons and patients agree on the goals of surgery, the degree to which they are aligned and what impact that discordance has on outcomes and in which subpopulations of patients remains poorly understood. Therefore, the proposed research will evaluate the impact of discordance in expectations on TJA immediate and long-term functional outcomes. The mentored phase of this proposal will evaluate the degree to which the phenomenon of discordance exists and what its correlates are. The independent phase will develop predictive models to examine the effect of this discordance on immediate as well as short and long-term outcomes. This study will use data from the Hospital for Special Surgery (HSS) CERT TJA registry, which was established in 2007 with support from AHRQ and has thus far enrolled more than 8000 patients. Subjects are evaluated preoperatively and followed up at 6 months and 2 years to assess satisfaction and changes in function. Expectations will be measured preoperatively using the validated HSS TJA expectations surveys.